.header {
  background: white;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}



.nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 30px;
}

.nav a {
  text-decoration: none;
  color: #666;
  font-weight: 500;
  transition: color 0.3s ease;
  padding: 8px 0;
}

.nav a:hover {
  color: #667eea;
}

.user-section {
  display: flex;
  align-items: center;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 15px;
}

.username {
  color: #333;
  font-weight: 500;
}

.logout-btn, .login-btn {
  padding: 8px 16px;
  border: 2px solid #667eea;
  background: transparent;
  color: #667eea;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
}

.logout-btn:hover, .login-btn:hover {
  background: #667eea;
  color: white;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .header-container {
    padding: 0 15px;
    flex-direction: column;
    height: auto;
    padding: 15px;
  }
  
  .nav ul {
    gap: 20px;
    margin: 15px 0;
  }
  
  .user-section {
    margin-top: 15px;
  }
}
